A platinum resistance temperature detector, a thermistor utilizing resistance-temperature characteristics of a semiconductor, a thermocouple using two kinds of metals, etc. are known as temperature sensors, specifically these are examples of contact-type temperature sensors. There are also many kinds of semiconductor temperature sensors utilizing temperature characteristics of the base-to-emitter voltage of transistors. Such a sensor is disclosed in, for example, Japanese Patent Application Kokai Publication No. 2004-294322.